The Heart (Cambridge (CIE) O Level Biology): Exam Questions

A scientist investigated the effect of different types of activity on the heart rate of participants, aged 21, after they had completed the activity for 10 minutes. 

The results are shown in Fig. 1.

Fig. 1

(i) State two control variables that the scientist should have kept constant throughout the investigation. 

[2]

(ii) Describe the results of the investigation.

[3]

Describe how the scientist could have measured and recorded heart rate.

Explain the effect of swimming on heart rate.

(i) State the name of the disease caused by a blockage in the arteries supplying the heart muscle.

[1]

(ii) List three risk factors that increase the risk of a blockage in the arteries supplying the heart muscle.

[3]

Fig. 1 is a diagram of the circulatory system. The blood vessels are labelled with letters.

Fig. 1

Complete Table 1 by identifying the letter of the named blood vessel in Fig. 1.

Table 1

Describe how the structures of the circulatory system maintain a one-way flow of blood.

The coronary arteries supply the heart muscle tissue with blood.

Fig. 1 shows a coronary artery with a blockage. 

Fig. 1

Explain the effect this blockage could have on heart muscle cells.

A blocked coronary artery can lead to coronary heart disease. 

Table 1 shows information about blood flow through coronary arteries in two people.

Person X was diagnosed with coronary heart disease while person Y does not have coronary heart disease.

Table 1

(i) Explain the difference in blood flow through the coronary arteries for persons X and Y.

[1]

(ii) Calculate the volume of blood flowing through the coronary arteries of person X in 1 hour.

Give your answer in dm³.

[2]

A blockage of the coronary artery can be caused by fatty deposits called plaques. Drugs called statins can be taken to help prevent a blockage. 

Fig. 2 shows the effects of the treatment of one person with four different statins (A, B, C and D) over a period of 10 years. The arrows show when each new treatment was started.

Fig. 2

Determine a conclusion on the effectiveness of the statin treatments in reducing the risk of coronary heart disease for this person.

The data was used to generate a report, with the claim: "Coronary heart disease can be cured by statins".

Evaluate the claim. 

Fig. 4.1 shows a blue whale, a marine mammal that has a heart weighing up to 600 kg.

Public domain, via rawpixel (opens in a new tab)

Fig. 4.1

In mammals, the wall of the left ventricle is approximately three times thicker than the wall of the right ventricle.

Explain why the muscle wall of the left ventricle is significantly thicker than the muscle wall of the right ventricle.